JP2020535604A - Heat-generating film and its manufacturing method - Google Patents

Abstract

The heat-generating film according to one embodiment of the present application is provided on a transparent base material, a coating layer having a refractive index of 1.450 to 1.485, and the coating layer. It is characterized in that the ten-point average roughness (Rz) of the surface of the metal foil pattern in contact with the coating layer, including the metal foil pattern, exceeds 0.9 μm.

Description

This application is the filing date of Korean Patent Application No. 10-2017-0168349 filed with the Korean Intellectual Property Office on December 8, 2017, and the Korean Patent Application filed with the Korean Intellectual Property Office on November 22, 2018. Claim the interests of No. 10-2018-0145328, all of which are incorporated herein by reference.

This application relates to a heat-generating film and a method for producing the same.

If there is a difference between the outside temperature and the inside temperature of the car, moisture or frost will be generated on the glass of the car. Heat-generating glass can be used to solve this problem. Heat-generating glass has the concept of attaching a heat ray sheet to the glass surface or forming heat rays directly on the glass surface and applying electricity to both terminals of the heat rays to generate heat from the heat rays, thereby raising the temperature of the glass surface. Use.

In particular, there are two major methods adopted to impart heat generation function to the front glass of an automobile with excellent optical performance.

The first method is to form a transparent conductive thin film on the entire surface of the glass. As a method of forming a transparent conductive thin film, there is a method of using a transparent conductive oxide film such as ITO, or a method of forming a thin metal layer and then using transparent insulating films above and below the metal layer to enhance transparency. .. Using this method has the advantage of being able to form an optically excellent conductive film, but has the disadvantage of not being able to achieve an appropriate amount of heat generation at a low voltage due to the relatively high resistance value.

In the second method, a metal pattern can be formed on the PET film by a printing step, or a metal layer can be formed on the PET film and then a metal pattern can be formed by a photolithography and etching steps. After the PET film on which the metal pattern is formed is inserted between two PVB films, a heat-generating product having a heat-generating function can be produced through a glass joining step. However, in the case of a method of etching after forming a metal layer on the PET film, when the thickness of the metal becomes thick, it must be formed by a method such as plating after vapor deposition of a seed layer. However, it has the disadvantage of being very expensive. The metal layer that hits the PET surface is a thin-film seed layer and a metal layer formed by sputtering. Since this has a low surface roughness (transparency) and glitters smoothly, PET is performed after patterning. From the surface, even if it is transparent, the pattern is easily recognized due to the reflectivity peculiar to metal. If the metal foil is bonded to PET with an adhesive and then patterned, the cost can be reduced. However, in this case, if the adhesive is completely cured in order to make it stable in etching and excellent in adhesive strength, the roughness corresponding to the surface roughness peculiar to the metal foil (roughness) will be the adhesive. It has the disadvantage of increasing the haze of the film and laminated glass that occurs on the surface of the. In addition to the essential elements PET and metal, the addition of other layers complicates the structure and may affect the physical properties of the final laminated glass.

This specification describes a heat-generating film and a method for producing the same.

One embodiment of the present application is
With a transparent base material
A coating layer provided on the transparent substrate and having a refractive index of 1.450 to 1.485,
Including a metal foil pattern provided on the coating layer
Provided is a heat-generating film having a ten-point average roughness (Rz) of a surface in contact with the coating layer of the metal foil pattern exceeding 0.9 μm.

In addition, other embodiments of the present application
A step of forming a coating layer having a refractive index of 1.450 to 1.485 on a metal foil film,
The step of forming a transparent substrate on the coating layer,
Including the step of patterning the metal foil film to form a metal foil pattern.
Provided is a method for producing a heat-generating film in which the ten-point average roughness (Rz) of the surface of the metal foil pattern in contact with the coating layer exceeds 0.9 μm.

In addition, other embodiments of the present application
With the heat-generating film
The first glass provided on any one surface of the heat generating film and
Including a second glass provided on the other side of the heat generating film.
Provided is an automobile heat-generating glass that includes a second laminated film on at least one surface of the surface between the heat-generating film and the first glass and the surface between the heat-generating film and the second glass.

According to one embodiment of the present application, a metal pattern is not formed by an expensive vapor deposition process as in the conventional case, but a coating layer is formed using a metal foil film as a base material, and then the metal foil film is patterned, so that the cost is low. Can be used to manufacture heat-generating films.

Further, the heat-generating glass for automobiles according to one embodiment of the present application can minimize the difference in refractive index between the laminated film provided on both sides of the heat-generating film and the coating layer provided in contact with the metal foil pattern. Therefore, the image distortion due to the heat generating glass can be minimized.

Further, the heat-generating glass for automobiles according to one embodiment of the present application has a low reflectance on at least one surface, so that the metal foil pattern can not be easily recognized.

It is a figure which shows schematicly the heat-generating film which concerns on one Embodiment of this application. It is a figure which shows the characteristic evaluation result of the heat-generating glass for an automobile by Example 1 of this application. It is a figure which shows the characteristic evaluation result of the heat-generating glass for an automobile by Example 2 of this application. It is a figure which shows the characteristic evaluation result of the heat-generating glass for an automobile by Example 3 of this application. It is a figure which shows the characteristic evaluation result of the heat-generating glass for an automobile by the comparative example 1 of this application. It is a figure which shows schematicly the heat-generating film which concerns on one Embodiment of this application. It is a figure which shows schematicly the heat-generating film which concerns on one Embodiment of this application. It is a figure which shows schematicly the heat-generating glass for automobile which concerns on one Embodiment of this application.

Hereinafter, the present invention will be described in more detail.

Conventionally, for the purpose of defrosting heat-generating glass for automobiles, metal wires are laminated and inserted into a PVB film of an intermediate layer for glass to realize resistance heat generation. However, the metal wire was visually recognized by the naked eye and the quality was deteriorated.

Further, as an alternative technology, a content has been developed in which 2 μm to 3 μm of copper is vapor-deposited or plated on PET and then patterned to apply a metal mesh film. However, a copper vapor deposition process for producing a metal mesh film has been developed. Since it is included, high cost is incurred. Further, the metal film including the vapor deposition step has a high reflectance of at least one surface without a separate step, and the metal mesh film produced from the metal film has a high reflectance and the pattern is easily recognized.

In order to reduce the cost, it is also possible to consider a method of using a raw fabric in which a metal foil such as a copper foil or an aluminum foil is attached to a transparent base material using an adhesive. However, since the metal foil and the transparent base material must be strongly adhered to each other, a completely curable adhesive is generally used. When the metal foil and the transparent base material are adhered with the completely curable adhesive, the metal foil is cured in a state where the unevenness of the metal foil is reflected on the surface of the adhesive as it is, and the metal is removed by etching. The unevenness remains as it is, the haze becomes high, and the appearance quality of the product is not good.

Therefore, in the present application, it is intended to provide a heat-generating film which can be manufactured at low cost, the pattern is not easily recognized, the haze after glass bonding is low, and the optical characteristics can be improved, and a manufacturing method thereof. To do.

The heat-generating film according to one embodiment of the present application is provided on a transparent base material, a coating layer having a refractive index of 1.450 to 1.485, and the coating layer. It is characterized in that the ten-point average roughness (Rz) of the surface of the metal foil pattern in contact with the coating layer, including the metal foil pattern, exceeds 0.9 μm.

In the present application, the transparent substrate is PET (polyethylene terephthalate), COP (polycarbonate polymer), PEN (polyethylene naphthalate), PES (polyethylene naphthalate), PES (polysulfone sulfone), PC (polysulfone acetyloid), PC (polycarbonate). The above film is preferable. In particular, the transparent substrate is more preferably PET. The thickness of the transparent substrate may be 25 μm to 100 μm, but is not limited to this.

For the transparent base material, an adhesion enhancing layer having a thickness of 1 nm to 5 nm is added to any one surface or both sides of the transparent base material in order to impart adhesion to the coating layer provided on the transparent base material. Can be included. The adhesion enhancing layer can be formed by a vapor deposition step or a solution coating step. The adhesion enhancing layer can contain, but is not limited to, one or more of niobium oxide, silicon oxide, tin oxide, titanium oxide, aluminum oxide and the like.

At this time, the niobium oxide may contain one or more substances in which the ratio of the number of Nb atoms to the number of O atoms is between 1 and 2.5. Specific examples include NbO, NbO ₂ , Nb ₂ O ₅ , Nb ₈ O ₁₉ , Nb ₁₆ O ₃₈ , Nb ₁₂ O ₂₉ , and Nb ₄₇ O ₁₁₆ . Further, the silicon oxide may contain one or more substances in which the ratio of the number of Si atoms to the number of O atoms is between 1 and 2. Specific examples include SiO ₂ and SiO. Further, the tin oxide may contain one or more substances in which the ratio of the number of Sn atoms to the number of O atoms is between 1 and 2. Specific examples include SnO ₂ and SnO. Further, the titanium oxide may contain one or more substances in which the ratio of the number of Ti atoms to the number of O atoms is between 0.3 and 2. Specific examples include TiO ₂ , TIO, Ti ₂ O ₃ , Ti ₃ O, and Ti ₂ O. The aluminum oxide contains Al ₂ O ₃ .

Further, another functional coating layer may be formed on the transparent substrate within the limit of maintaining the transparency of the film. Further, an amine-based or epoxy-based primer can be coated on the transparent substrate.

In the present application, the coating layer is provided on a transparent substrate and has a refractive index of 1.450 to 1.485. The refractive index of the coating layer is more preferably 1.465 to 1.485.

In the present application, the refractive index of the coating layer, the protective layer, the laminated film, etc. is determined by the prism coupler (example of the device-Metricon 2010 / M), the ellipsometer (example of the device-UVISEL of Horiba Scientific). , Abbe refractometer (Abbe Refractometer; example of device-AR4 of Kruss) and the like.

Generally, the front glass of an automobile is manufactured by inserting a mating film between two flat glass sheets and laminating them at high temperature and high pressure. At this time, polyvinyl butyral (PVB), ethyl vinyl acetate (EVA) and the like are often used as the laminated film, but the refractive index of these materials is 1.45 to 1.49, and most of them are It is 1.47 to 1.48. If the refractive index of the coating layer / laminated film is the same or the difference is small after the glass is bonded, the haze can be reduced. Therefore, it is preferable to adjust the refractive index of the coating layer to 1.450 to 1.485. If the refractive index of the coating layer has a large difference from the refractive index of the combined film, light will have a high haze due to internal scattering while passing through the glass, which becomes even more severe when the unevenness of the coating layer is large.

Further, the thickness of the coating layer may be 3 μm to 15 μm, 3 μm to 7 μm, or 7 μm to 15 μm. Further, the thickness of the coating layer may be 5 μm to 7 μm. When the thickness of the coating layer is less than 3 μm, the adhesion to the transparent base material is not sufficient, and it is difficult to uniformly coat the entire area of the metal foil having large irregularities. When the thickness of the coating layer exceeds 15 μm, the coating layer material is wasted, the solvent is difficult to dry, and the thick coating layer is stably formed on the copper foil which is relatively thin as compared with the coating layer. Difficult to manufacture. Further, after manufacturing the heat-generating film, the metal foil pattern may be deformed and pulled or broken when the film and glass are laminated on both sides of the heat-generating film and bonded at high temperature / high pressure. ..

In addition, the coating layer may contain one or more of polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), and an acrylate-based adhesive material. In particular, the coating layer more preferably contains polyvinyl butyral (PVB).

The glass transition temperature (Tg) of the coating layer may be 25 ° C to 80 ° C. When the glass transition temperature of the coating layer is less than 25 ° C., it is difficult to stably store the produced heat-generating film at room temperature. In addition, when the heat-generating film is laminated with the combined film and glass and bonded at high temperature / high pressure, if the glass transition temperature of the coating layer is low, the fluidity becomes even higher, and the metal foil pattern is deformed and pulled. , It becomes even more vulnerable to disconnection. When the glass transition temperature of the coating layer exceeds 80 ° C., lamination with a transparent substrate by heat is difficult.

In the present application, the metal foil pattern is provided on the coating layer, and the ten-point average roughness (Rz) of the surface of the metal foil pattern in contact with the coating layer is over 0.9 μm. The ten-point average roughness (Rz) of the surface of the metal foil pattern in contact with the coating layer may be more than 0.9 μm and less than 3.0 μm. Further, the ten-point average roughness (Rz) of the entire opposite surface of the surface of the coating layer provided with the transparent substrate may exceed 0.9 μm or less than 3.0 μm.

When the Rz is 0.9 μm or less, it has a high reflectance peculiar to a metal foil due to low unevenness. Therefore, since it is difficult to reduce the reflectance of the heat-generating film and heat-generating glass produced from this, there is a drawback that the pattern is easily recognized by the eyes due to the high reflectance.

The height of the metal foil pattern may be 2 μm to 15 μm, and the metal foil pattern may include an aluminum foil pattern or a copper foil pattern. At this time, the height of the metal foil pattern can be measured with a micrometer or a thickness gauge.

The metal foil pattern can be produced from a metal foil containing at least one matt surface having a relatively high ten-point average roughness (Rz). At this time, the matte surface of the metal foil comes into contact with the coating layer.

In the present application, the reflectance of the metal foil at a wavelength of 380 nm to 780 nm measured on a matte surface having a relatively high ten-point average roughness (Rz) may be 67% or less, preferably 50% or less. There may be. Further, the metal foil pattern may include an aluminum foil pattern or a copper foil pattern having an average reflectance of 15% or less at a wavelength of 380 nm to 780 nm.

The reflectance can be measured with a device such as UV-3600 or Solidspec-3700 manufactured by Shimadzu Corporation of Japan.

The line width of the metal foil pattern may be 4 μm to 25 μm, the surface resistance may be 0.1 ohm / sq to 0.5 ohm / sq, and the aperture ratio may be 90% to 99%. The aperture ratio means the ratio of the upper area of the coating layer not provided with the metal foil pattern to the total upper area of the coating layer. Further, the total length of the lines of the metal foil pattern included in the area of 25 cm ² may be ² m to 11 m.

In one embodiment of the present application, a blackening layer pattern or a polymer resin layer pattern can be additionally included on the metal foil pattern. The blackened layer pattern may contain one or more substances such as chromium-based, selenium-based, copper sulfide-based, copper oxide-based, copper sulfide-based, aluminum nitride-based, and copper oxynitride-based. The blackened layer pattern is formed by wet coating the above-mentioned substance on a metal foil pattern, or a substance such as an aluminum nitride-based material or a copper oxynitride-based material is sputtered from 30 nm to 70 nm. Can be formed.

The polymer resin layer pattern may contain an acrylate-based resin, a novolak resin, or the like, and may additionally contain a black dye, a pigment, or the like in order to improve the appearance. The thickness of the polymer resin layer pattern may be 100 nm to 500 nm, but is not limited to this.

In one embodiment of the present application, a protective layer may be additionally included on the coating layer and the metal foil pattern, and the difference in refractive index between the coating layer and the protective layer may be 0.030 or less. It may be 0 or more.

The protective layer may contain, but is not limited to, resins such as PVB (polyvinyl butyral), EVA (ethylene vinyl acetate), PU (polyurethane), and PO (Polyolefin). In particular, the protective layer preferably contains PVB (polyvinyl butyral).

The advantages when the protective layer is additionally included on the coating layer and the metal foil pattern are as follows. When the line height of the metal foil pattern becomes high, it becomes very difficult to attach the protective film due to the unevenness of the pattern. If the product is released without the protective layer, there is a possibility of damage such as surface scratches. At this time, if a PVB coating layer made of a material such as PVB applied to the laminated glass is introduced on the upper part of the pattern surface, the metal surface can be protected from surface scratches. Further, even when scratches occur in the PVB coating layer, the scratches can be removed by the heat and pressure at the time of laminating the glass.

The method of including the protective layer on the coating layer and the metal foil pattern is as follows. A composition containing the above-mentioned material is coated on another release film to form a thickness of 3 μm to 30 μm, and then heat lamination is performed at 70 ° C. to 130 ° C. to form the metal foil pattern on the metal foil pattern by a process. can do. At this time, the thermal lamination step can be performed except for the portion in contact with the bus bar. By heat fusion by the heat lamination step, the surface roughness of the coating layer having a refractive index of 1.450 to 1.485 can be reduced. As the release film, a film obtained by coating PET with a silicone-based release layer or a melamine-based release layer can be used. The release film can be removed immediately after the thermal lamination step, and may be removed immediately before encapsulation between PVB sheets during the production of heat-generating glass for automobiles, or immediately before the glass is bonded. It may be removed.

In another embodiment of the present application, a first laminated film is additionally included on the opposite surface of the surface provided with the coating layer of the transparent substrate, and the difference in refractive index between the coating layer and the first laminated film. May be 0.030 or less, and may be 0 or more.

The first laminated film can include, but is not limited to, PVB (polyvinyl butyral), EVA (ethylene vinyl acetate), PU (polyurethane), PO (Polyolefin) and the like. In particular, the first laminated film preferably contains PVB (polyvinyl butyral).

In one embodiment of the present application, the coating layer and the protective layer can contain the same material, and the coating layer and the first laminated film can contain the same material. Therefore, the coating layer and the protective layer can contain PVB (polyvinyl butyral), and the coating layer and the first laminated film can contain PVB (polyvinyl butyral).

The protective layer may be formed by coating another release film with a composition containing the above-mentioned material to form a thickness of 3 μm to 30 μm, and then using a thermal lamination step at 70 ° C. to 130 ° C. it can. At this time, the thermal lamination step can be performed except for the portion in contact with the bus bar. By heat fusion by the heat lamination step, the surface roughness of the coating layer having a refractive index of 1.450 to 1.485 can be reduced.

As the release film, a film obtained by coating PET with a silicone-based release layer or a melamine-based release layer can be used. The release film can be removed immediately after the thermal lamination step, and may be removed immediately before encapsulation between PVB sheets during the production of heat-generating glass for automobiles, or immediately before the glass is bonded. It may be removed.

If the line height of the metal foil pattern is high, it becomes very difficult to attach the protective film due to the unevenness of the pattern. Therefore, if the metal foil pattern is sold without the protective film, there is a possibility of damage such as surface scratches. At this time, if a PVB coating layer made of a material such as PVB applied to the laminated glass is formed on the upper part of the pattern surface, the metal surface can be protected from surface scratches. Further, even when scratches occur in the PVB coating layer, the scratches can be removed by the heat and pressure at the time of laminating the glass.

The heat-generating film according to one embodiment of the present application is schematically shown in FIGS. 1, 6 and 7 below. As shown in FIG. 1 below, the heat generating film according to one embodiment of the present application is provided on the transparent base material 10 and the transparent base material 10, and has a refractive index of 1.450 to 1.485. A ten-point average roughness (Rz) of at least one of the surfaces of the coating layer or the metal foil pattern 30 in contact with the coating layer 20, including the metal foil pattern 30 provided on the coating layer 20 and the coating layer 20. Is over 0.9 μm.

Further, as shown in FIG. 6 below, the heat-generating film according to one embodiment of the present application additionally contains a protective layer 40 on the coating layer 20 and the metal foil pattern 30, and the coating layer 20 and the protective layer 40 are additionally included. The difference in refractive index between the two is 0.030 or less. At this time, the protective layer can include, but is not limited to, PVB (polyvinyl butyral), EVA (ethylene vinyl acetate), PU (polyurethane), PO (Polyolefin) and the like. In particular, the protective layer preferably contains PVB (polyvinyl butyral).

Further, as shown in FIG. 7 below, the heat-generating film according to one embodiment of the present application additionally contains the first laminated film 50 on the opposite surface of the surface of the transparent base material 10 provided with the coating layer 20. The difference in refractive index between the coating layer 20 and the first laminated film 50 is 0.030 or less. At this time, the first laminated film can include, but is not limited to, PVB (polyvinyl butyral), EVA (ethylene vinyl acetate), PU (polyurethane), PO (Polyolefin) and the like. In particular, the first laminated film preferably contains PVB (polyvinyl butyral).

The method for producing a heat-generating film according to an embodiment of the present application includes a step of forming a coating layer having a refractive index of 1.450 to 1.485 on a metal foil film and forming a transparent base material on the coating layer. The ten-point average roughness (Rz) of the surface of the metal foil pattern in contact with the coating layer is more than 0.9 μm, including the step of patterning the metal foil film to form the metal foil pattern. It is characterized by.

In the method for producing a heat-generating film according to an embodiment of the present application, the contents relating to the metal foil film, the coating layer, the transparent base material, and the like are the same as those described above.

In the present application, when the thickness of the metal foil film is 5 μm or less, a carrier layer can be introduced on the back surface of the metal foil film for ease of handling. The carrier layer may be a copper foil or an aluminum foil.

In the present application, the step of forming the coating layer having a refractive index of 1.450 to 1.485 on the metal foil film is a composition containing the above-mentioned coating layer material and a solvent capable of dissolving the coating layer. It is performed by a coating method using an object, and the coating method can utilize a comma coating, a gravure coating, a slot die coating, or the like. The solvent is not particularly limited as long as it can dissolve the material for the coating layer, and for example, methanol, ethanol, isopropanol, methyl ethyl ketone, NMP, cellosolve-based substances, and mixtures thereof may be used. Can be done.

In the present application, the step of forming the transparent base material on the coating layer is carried out by a thermal lamination step at about 60 ° C. to 120 ° C., which is equal to or higher than the softening point temperature of the coating layer. At this time, a carrier film can be attached to the transparent base material for the purpose of process protection, prevention of foreign matter contamination, and the like.

In the present application, the step of patterning the metal foil film to form a metal foil pattern can utilize a usual resist patterning step known in the art. That is, after forming a resist pattern on the metal foil film, the metal foil pattern can be formed by an etching step.

The method for producing a heat-generating film according to an embodiment of the present application is a step of forming the metal foil pattern and then forming a protective layer on the coating layer and the metal foil pattern, and / or the coating layer of the transparent base material. An additional step of forming a protective layer on the opposite surface of the surface provided with the can be included.

The heat-generating glass for automobiles according to one embodiment of the present application includes the heat-generating film, the first glass provided on any one surface of the heat-generating film, and the second glass provided on the other surface of the heat-generating film. At least one surface of the surface between the heat-generating film and the first glass and the surface between the heat-generating film and the second glass includes a second laminated film.

The second laminated film is not particularly limited, and a laminated film known in the art can be applied. More specifically, the second laminated film can include PVB (polyvinyl butyral), EVA (ethylene vinyl acetate), PU (polyurethane), PO (polyolefin), and the like, but is not limited to these. Absent. In particular, the second laminated film preferably contains PVB (polyvinyl butyral).

In the present application, the first glass and the second glass are not particularly limited, and glasses known in the art can be applied.

In the present application, the haze of the heat-generating glass for automobiles may be 0.3% to 2%.

According to another embodiment of the present application, it further comprises a pair of opposing busbars for applying electricity to the metal foil pattern.

According to another embodiment of the present application, a black pattern is provided to conceal the busbar. For example, the black pattern can be printed using a paste containing a cobalt oxide. At this time, screen printing is suitable for the printing method, and the thickness can be set to 10 μm to 100 μm. The metal pattern and the bus bar may be formed before or after the formation of the black pattern, respectively.

The heat-generating glass for automobiles according to the present application is connected to a power source for heat generation, and at this time, the amount of heat generated is preferably 100 W to 1,000 W, preferably 200 W to 700 W per m ² . The heating element for automobiles according to the present application is excellent in heat generation performance even when the heating element has a low voltage, for example, 30 V or less, preferably 20 V or less.

The heat-generating glass for automobiles according to one embodiment of the present application is schematically shown in FIG. 8 below.

According to one embodiment of the present application, a metal pattern is not formed by an expensive vapor deposition process as in the conventional case, but a coating layer is formed using a metal foil film as a base material, and then the metal foil film is patterned, so that the cost is low. Can be used to manufacture heat-generating films.

Further, the heat-generating glass for automobiles according to one embodiment of the present application can minimize the difference in refractive index between the laminated film provided on both sides of the heat-generating film and the coating layer provided in contact with the metal foil pattern. Therefore, the image distortion due to the heat generating glass can be minimized.

Further, since the heat-generating glass for automobiles according to one embodiment of the present application has low reflectance on at least one surface, the metal foil pattern can be prevented from being easily recognized.

Hereinafter, embodiments described in the present specification will be illustrated through examples. However, the following examples are not intended to limit the scope of the embodiment.

<Example>

<Example 1>
A coating liquid having a composition of 12 parts by weight of PVB, 44 parts by weight of ethanol, and 44 parts by weight of methyl ethyl ketone having a refractive index of 1.47 and a glass transition temperature (Tg) of 32 ° C. was applied to a matt surface of copper foil having a thickness of 3 μm and 8 μm. After coating, it was dried at 120 ° C. for 10 minutes to form a PVB layer having a thickness of 5 μm to 7 μm on the matt surface of the copper foil. At this time, the Rz of the matt surface of the 3 μm copper foil was 1.5 μm, and the Rz of the 8 μm copper foil was 1.63 μm. On the other hand, the average reflectance of the matt surface measured at a wavelength of 380 nm to 780 nm was 7.6% with respect to the copper foil of 3 μm.

After that, a base material was produced by laminating a PET having a thickness of 50 μm on the PVB surface of the copper foil at a speed of 80 ° C. and 4 mpm. In the case of a copper foil having a thickness of 3 μm, a carrier foil of 18 μm was attached to the back surface for ease of handling in the film process, and this was removed before forming the pattern. Then, the copper foil was washed / washed / dried with 0.5 wt% sulfuric acid, and then a 10 μm-thick dry film rest (DFR) was laminated on the copper surface at 110 μm. After that, a heat-generating film was produced through photolithography, development, etching, and peeling steps. At this time, a 0.4 wt% aqueous solution of potassium carbonate was used as the developing solution, a 20 wt% iron chloride-based aqueous solution was used as the etching solution, and a 2% sodium hydroxide aqueous solution was used as the stripping solution.

After that, copper foils with a width of 1 cm and a thickness of 50 μm are attached to both ends where current flows on the pattern surface of the heat generating film, a PVB sheet with a thickness of 0.38 mm on both sides, and a thickness of 2.8 mm on the outermost layer. A glass / PVB sheet / heat-generating film / PVB sheet / glass structure was formed by laminating the glass, and then vacuum lamination was performed at a temperature of 140 ° C. for 30 minutes to produce a heat-generating laminated glass. The physical properties of the laminated glass are shown in FIG. 2 below.

<Example 2>
A coating liquid having a composition of 14 parts by weight of PVB, 43 parts by weight of ethanol, and 43 parts by weight of methyl ethyl ketone having a refractive index of 1.47 and a glass transition temperature (Tg) of 32 ° C. was coated on the matt surface of a copper foil having a thickness of 3 μm. Then, it was dried at 120 ° C. for 3 minutes to form a PVB layer having a thickness of 5 μm to 7 μm, and then heat-laminated with PET having a thickness of 50 μm with a hot roll laminator at 110 ° C. to produce a base material. At this time, the surface roughness of the matt surface of the 3 μm copper foil used was 1.5 μm, and the average reflectance measured at a wavelength of 380 nm to 780 nm was 6.7%. In the case of a copper foil having a thickness of 3 μm, a carrier foil of 18 μm was attached to the back surface for ease of handling in the film process, and this was removed before forming the pattern. A novolak resin-based resist pattern having a thickness of 100 nm to 400 nm was formed in the printing step, and then etched with an etching solution based on 5% sulfuric acid / 5% hydrogen peroxide to produce a heat-generating film without a resist removing step.

After that, copper foils with a width of 1 cm and a thickness of 50 μm are attached to both ends where current flows on the pattern surface of the heat-generating film, a PVB sheet with a thickness of 0.38 mm on both sides, and a thickness of 2.8 mm on the outermost layer. A glass / PVB sheet / heat-generating film / PVB sheet / glass structure was formed by laminating the glass, and then vacuum lamination was performed at a temperature of 140 ° C. for 30 minutes to produce a heat-generating laminated glass. The physical properties of the laminated glass are shown in FIG. 3 below.

<Example 3>
Example 2 is applied to a copper foil having a thickness of 3 μm in which the surface roughness of the matt surface is 1.5 μm and the average reflectance measured at a wavelength of 380 nm to 780 nm is 6.7% with respect to this surface. A coating liquid having a composition of 14 parts by weight of PVB, 43 parts by weight of ethanol, and 43 parts by weight of methyl ethyl ketone having a refractive index of 1.47 and a glass transition temperature (Tg) of 32 ° C. was applied to a copper foil having a thickness of 3 μm in the same manner as in the above. After coating on the matt surface of the above, it was dried at 120 ° C. for 3 minutes to form a PVB layer having a thickness of 5 μm to 7 μm. After that, the resist was removed with a 3% NaOH aqueous solution on the film that had undergone PET lamination, removal of the carry foil having a back surface of 18 μm, resist pattern formation, and copper etching in the same manner as in Example 2, and then the selenium base was used. The copper surface exposed to air was blackened by immersing it in a blackening solution for 30 seconds. At this time, in order to strengthen the adhesion between the PET film and the PVB sheet and the PVB coating layer, a PET film (thickness 50 μm) having a 2.5 nm NbOx layer deposited on both sides was used as the PET.

After that, a PVB sheet having a thickness of 0.38 mm is laminated on both sides of the heat-generating film and glass is laminated on the outermost layer to provide a glass / PVB sheet / heat-generating film / PVB sheet / glass structure, and then 140. A heat-generating laminated glass was produced by vacuum lamination at a temperature of ° C. for 30 minutes. The physical properties of this laminated glass are shown in FIG. 4 below.

<Comparative example 1>
A heat-generating film was produced by a resist patterning, etching, and peeling step using a base material in which an adhesive layer containing a silicone-based polymer having a refractive index of 1.44 as a main component was formed between PET and a copper foil. At this time, the thickness of the copper foil after removing the carrier foil was 2 μm. The optical characteristics in the film state and the optical characteristics after glass bonding are shown in FIG. 5 below for the films when only the etching is advanced and when the resist is peeled off.

Compared with the above example, when the refractive index of the PVP coating layer was 1.47 (Examples 1 to 3), the haze after glass bonding was less than 2%, whereas the refractive index was 1. In the case of Comparative Example 1 which is 44, it was found that the haze was 2% or more even after the glass was bonded.

<Comparative example 2>
A coating liquid having a composition of 20 parts by weight of PVB and 80 parts by weight of N-methylpyrrolidone having a refractive index of 1.47 and a glass transition temperature (Tg) of 32 ° C. is applied to a copper foil having a surface roughness of Rz of 2.0 μm and a thickness of 2 μm. After coating on the matt surface of the copper foil, it was left at room temperature for 10 minutes and then dried at 110 ° C. for 3 minutes, or dried with another temperature profile to form a PVB layer having a thickness of 50 μm on the copper foil. .. At this time, when dried at 80 ° C. for 10 minutes and 110 ° C. for 3 minutes after being left over night at room temperature, the curl of the copper foil / PVB base material was very severe, and lamination with PET was difficult. When increasing the drying rate, bubbles were observed after lamination with PET due to the solvent remaining inside the substrate.

<Comparative example 3>
After coating a copper foil with a thickness of 6 μm with a coating liquid having a composition of 12 parts by weight of PVB sheet, 44 parts by weight of ethanol, and 44 parts by weight of methyl ethyl ketone having a refractive index of 1.47 and a glass transition temperature (Tg) of 32 ° C. , 120 ° C. for 4 minutes to form a PVB layer with a thickness of 5 μm to 7 μm. At this time, the Rz of the 6 μm copper foil used was 0.7 μm, and the average reflectance of the matt surface measured at a wavelength of 380 nm to 780 nm was 68%. In this case, even after thermal lamination of PET having a thickness of 50 μm on the PVB surface of the copper foil at a speed of 120 ° C. and 1.7 mpm, the adhesion between the copper foil / PVB layer and the PET layer cannot be secured and the process cannot be performed. Finally, additional aging was required at 110 ° C. for 3 days to produce the substrate.

Then, a DFR having a thickness of 10 μm was thermally laminated with the copper foil surface at 120 ° C., and then a heat-generating film was produced through photolithography, development, etching, and peeling steps. At this time, a 1.7 wt% aqueous solution of sodium carbonate was used as the developing solution, an aqueous solution based on 5% sulfuric acid / 5% excess water was used as the etching solution, and a 2.5% aqueous solution of sodium hydroxide was used as the stripping solution. After that, a PVB sheet having a thickness of 0.38 mm was laminated on both sides and a glass having a thickness of 2.8 mm was laminated on the outermost layer to provide a glass / PVB sheet / heat generating film / PVB sheet / glass structure. After that, heat-generating laminated glass was produced by vacuum lamination at a temperature of 140 ° C. for 30 minutes. The reflectance after bonding at this time was slightly high at 15% to 17%.

<Comparative example 4>
An adhesive layer containing an epoxy polymer having a refractive index of 1.612 as a main component was formed between PET and a copper foil, and a base material aged at 60 ° C. for 1 day was prepared. A heat-generating film was produced by resist patterning, etching, and peeling steps. At this time, the thickness of the copper foil after removing the carrier foil was 2 μm. After that, a PVB sheet having a thickness of 0.38 mm is laminated on both sides of the heat generating film, and glass is laminated on the outermost layer to provide a glass / PVB sheet / heat generating film / PVB sheet / glass structure, and then 120. After vacuum lamination at a temperature of ° C. for 20 minutes, vacuum lamination was performed at a temperature of 140 ° C. for 20 minutes to produce a heat-generating laminated glass. The haze of the heat-generating laminated glass produced in this way was 3.5%.

<Comparative example 5>
An attempt was made to prepare a base material in which an adhesive layer mainly composed of a urethane polymer having a refractive index of 1.492 was formed between PET and a copper foil, and to produce a heat-generating film by resist patterning, etching, and peeling steps. did. The thickness of the copper foil was 8 μm. At this time, when etching was performed using an etching solution composed of a mixed solution of phosphoric acid / nitric acid / acetic acid, the urethane-based polymer layer was damaged and patterning could not proceed. It was difficult to proceed with stable patterning even when an etching solution containing sulfuric acid and hydrogen peroxide as the main components was used, but PVB with a thickness of 0.38 mm on both sides for some good regions. After laminating the sheet and glass on the outermost layer to provide a glass / PVB sheet / heat-generating film / PVB sheet / glass structure, vacuum lamination was performed at a temperature of 140 ° C. for 30 minutes to produce a heat-generating laminated glass. The haze of the heat-generating laminated glass produced in this way was 2.6%.

In the present application, the light characteristic of the transmission mode is measured by COH-400 of Nippon Denshoku Co., Ltd., and the light characteristic of the reflection mode is measured by Solidspec-3700 of Shimadzu Co., Ltd. The case of irradiating the PET surface with light was defined as "front" and "rear". When a voltage was applied, the terminal resistance was calculated from the current flowing between the two busbars, divided by the distance between the busbars, and then multiplied by the width of the region where the current flows to calculate the surface resistance.

As described above, according to one embodiment of the present application, the metal foil film is formed after the coating layer is formed using the metal foil film as a base material without forming the metal pattern by the conventional expensive vapor deposition process. Since the patterning is performed, the heat-generating film can be manufactured at low cost.

Further, the heat-generating glass for automobiles according to one embodiment of the present application can minimize the difference in refractive index between the laminated film provided on both sides of the heat-generating film and the coating layer provided in contact with the metal foil pattern. Therefore, the image distortion due to the heat generating glass can be minimized.

Further, the heat-generating glass for automobiles according to one embodiment of the present application has a low reflectance on at least one surface, so that the metal foil pattern can not be easily recognized.

10: Transparent base material 20: Coating layer 30: Metal foil pattern 40: Protective layer 50: Laminated film 60: Glass

Claims (25)

With a transparent base material
A coating layer provided on the transparent substrate and having a refractive index of 1.450 to 1.485,
Including a metal foil pattern provided on the coating layer
A heat-generating film having a ten-point average roughness (Rz) of a surface in contact with the coating layer of the metal foil pattern exceeding 0.9 μm. The heat-generating film according to claim 1, wherein the entire surface opposite to the surface of the coating layer provided with the transparent substrate has a ten-point average roughness (Rz) of more than 0.9 μm. The heat-generating film according to claim 1 or 2, wherein the refractive index of the coating layer is 1.465 to 1.485. The heat-generating film according to any one of claims 1 to 3, wherein the thickness of the coating layer is 3 μm to 15 μm. The heat-generating film according to any one of claims 1 to 3, wherein the coating layer has a thickness of 3 μm to 7 μm. The heat-generating film according to any one of claims 1 to 3, wherein the coating layer has a thickness of 7 μm to 15 μm. The coating layer contains one or more of polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), and an acrylate-based adhesive material.
The heat-generating film according to any one of claims 1 to 6, wherein the glass transition temperature (Tg) of the coating layer is 25 ° C to 80 ° C. The heat-generating film according to any one of claims 1 to 7, wherein the height of the metal foil pattern is 2 μm to 15 μm. The heat-generating film according to any one of claims 1 to 8, wherein the metal foil pattern includes an aluminum foil pattern or a copper foil pattern. The heat-generating film according to any one of claims 1 to 9, wherein the metal foil pattern includes an aluminum foil pattern or a copper foil pattern having an average reflectance of 15% or less at a wavelength of 380 nm to 780 nm. The heat-generating film according to any one of claims 1 to 10, wherein the metal portion of the metal foil pattern has an average reflectance of 67% or less at a wavelength of 380 nm to 780 nm. The heat-generating film according to any one of claims 1 to 11, wherein the line width of the metal foil pattern is 4 μm to 25 μm. The heat-generating film according to any one of claims 1 to 12, wherein a blackening layer pattern or a polymer resin layer pattern is additionally included on the metal foil pattern. 13. The blackening layer pattern includes one or more of chromium-based, selenium-based, copper sulfide-based, copper oxide-based, copper sulfide-based, aluminum oxynitride-based, and copper oxynitride-based. The heat generating film described in. The heat-generating film according to claim 13, wherein the polymer resin layer pattern contains a novolak resin or an acrylate-based resin. An additional protective layer is included on the coating layer and the metal foil pattern.
The heat-generating film according to any one of claims 1 to 15, wherein the difference in refractive index between the coating layer and the protective layer is 0.030 or less. The heat-generating film according to claim 16, wherein the protective layer has a thickness of 3 μm to 30 μm. The heat-generating film according to claim 16 or 17, wherein the coating layer and the protective layer contain the same material. An additional first laminated film is included on the opposite surface of the surface provided with the coating layer of the transparent substrate.
The heat-generating film according to any one of claims 1 to 18, wherein the difference in refractive index between the coating layer and the first laminated film is 0.030 or less. The heat-generating film according to claim 19, wherein the coating layer and the first laminated film contain the same material. The heat-generating film according to claim 20, wherein the coating layer and the first laminated film contain polyvinyl butyral (PVB). A step of forming a coating layer having a refractive index of 1.450 to 1.485 on a metal foil film,
The step of forming a transparent substrate on the coating layer,
Including the step of patterning the metal foil film to form a metal foil pattern.
A method for producing a heat-generating film, wherein the ten-point average roughness (Rz) of the surface in contact with the coating layer of the metal foil pattern exceeds 0.9 μm. The method for producing a heat-generating film according to claim 22, wherein the step of forming the transparent base material on the coating layer is performed by a thermal lamination step of the coating layer and the transparent base material at 60 ° C. to 120 ° C. The heat-generating film according to any one of claims 1 to 21 and
The first glass provided on any one surface of the heat generating film and
Including a second glass provided on the other side of the heat generating film.
A heat-generating glass for automobiles, wherein at least one surface of the surface between the heat-generating film and the first glass and the surface between the heat-generating film and the second glass includes a second laminated film. The heat-generating glass for automobiles according to claim 24, wherein the second laminated film contains one or more of polyvinyl butyral (PVB) and ethylene vinyl acetate (EVA).